ON SOME JAPANESE CALCAREOUS SPONGES. 11 



The gîisfcral skeleton consists of the paired rays of subgastral 

 sagittal triradiates, of triradiatos, and of the facial rays of quadri- 

 radiates. Of the last, the short apical rays project into the gastral 

 cavity. Triradiates and quadriradiates are disposed tangentially, 

 otherwise in no definite orientation. The former are always less 

 numerous than the latter. 



The skeleton of the oscular margin consists in a close inter- 

 lacement of fine longitudinal trichoxea and of triradiates and quadri- 

 radiates, both which have strongly divergent paired rays and 

 downwardly directed basal ray. To the above there may be added 

 a number of large oxea which run longitudinally and parallel with 

 trichoxea. 



Spicules. 



Dermal triradiates (textfig. 2, (t, h). — Slightly sagittal. All 

 rays straight, smooth and gradually sharp-pointed. Basal ray 

 slightly longer than paired rays, equally thick or a little thicker 

 than these, 240-370 /^ long and 20-28 /^ thick. Paired rays of 

 nearly equal length, 200-270 p- long and 20 ,« thick. 



Subdermal triradiates (textfig. 2, c, d, c). — Pseudosagittal, ir- 

 regular. All rays of nearly same thickness but of different length 

 and shape. Basal ray much longer than paired rays, sharp-pointed, 

 its basal parts slightly curved and for the rest straight or nearly 

 so, 200-490/^ long and 16-20/^ tliick. Paired rays are of diff'erent 

 length and shape, lying not in the same plane with basal ray. 

 The longer of them gradually tapers to a sharp point, is bent near 

 base and is sometimes more or less crooked in the remaining parts, 

 100-160/^- long and 12-16/^ thick. The shorter ray is sharp- 

 pointed and strongly curved in the middle parts, 90-110/^- long 

 and 16-20,« thick. 



